A low-noise amplifier (LNA) may be used in the front-end receiver of a system to amplify an input signal, and output the amplified signal to other circuitry (e.g., tuner, demodulator, etc.) in the system for further processing. In order for the system to achieve high input sensitivity, it is important that the LNA have low noise and high linearity.
In a conventional LNA, linearity is limited by gm*Ro, where gm is the transconductance of the LNA and Ro is the output impedance of the LNA. As a result, the conventional LNA requires high current, and therefore high power, to achieve high linearity. In a convention LNA, inductors may be used to achieve low noise. However, inductors occupy a large chip area, significantly increasing the size of the LNA.